A range of different bespoke polyurethane (BPU) cushioning materials were manufactured, using standard footwear manufacturing techniques and commercially available chemical compounds. These materials produced had the same mechanical qualities but differed in how stiff they were. Various mechanical tests were then performed using a 3D-printed model of a heel, as well as the feet of ten healthy adult volunteers. Pressure measurements were taken of the entire area of the foot to assess the mechanical characteristics and especially the cushioning properties of the insole materials being tested.
The results indicate that optimising the stiffness of cushioning materials can reduce pressure during standing and walking by at least 16% and 19% respectively. The type of material that minimizes pressure at best when a person stands or walks was also found to differ. Stiffer materials are for instance needed for walking.
This means that health workers should consider different cushioning material for their highly active patients compared to those who lead sedentary lives.
